Iranian Foreign Minister Mohammad Javad Zarif has slammed the United States’ defiance to honor its obligations under the spirit and letter of the landmark 2015 nuclear agreement signed between Iran and the P5+1 group of countries.

“We’ll see if US prepared to live up to letter of the JCPOA (the nuclear deal, known as the Joint Comprehensive Plan of Action) let alone [its] spirit. So far, it has defied both” Zarif said on his official Twitter account on Friday.

“Should I use my highlighter again?” he asked, referring to his Ttweet that highlighted a part of the JCPOA text about the parties' commitments.

Zarif made the comments after US Secretary of State Rex Tillerson said on Tuesday that Iran is sticking to the terms of the JCPOA. However, he accused Iran of supporting terrorism and questioned whether sanctions should keep being lifted.

He said US President Donald Trump’s administration was reviewing the lifting of sanctions against Iran, leveling the allegation that Tehran remains a sponsor of terrorism.

Iran and the five permanent members of the United Nations Security Council -- the United States, Britain, France, China and Russia -- plus Germany signed the JCPOA on July 14, 2015 and started implementing it on January 16, 2016.

Under the agreement, limits were put on Iran’s nuclear activities in exchange for, among other things, the removal of all nuclear-related bans against the Islamic Republic.

The UN Security Council later unanimously endorsed a resolution that effectively turned the JCPOA into international law.

The International Atomic Energy Agency has on multiple occasions verified Iran’s adherence to its commitments under the JCPOA.